Acronis and Buffalo TerraStation

We have been using Acronis successfully for several years now with minimal problems. We recently purchased a Buffalo TerraStation TS5800D032. I was able to successfully copy all of the files from my vaults to the share I created on the TerraStation i.e. NAS1. I then was able to remove the vaults one at a time from the old location and add them using the new location on NAS1. So far so good. I then created a test vault using Acronis, including directory creation. I then created a new backup plan with the new vault on NAS1. It runs for a few minutes and then errors out. Looking at the log, it says that the user was not authenticated. I have turned off the security on the share. I did create a new user. The computer I use for Acronis is in our domain but the NAS is on a separate private network that has no access to the domain. It is in a workgroup. Acronis server is at 192.168.1.100 and NAS is at 192.168.1.102. What am I missing here? I need this to work.